Thermostatic dual switch with improved manual control



March 15, 1966 w. HUFFMAN 3,240,906

THERMOSTATIC DUAL SWITCH WITH IMPROVED MANUAL CONTROL Filed May 8, 1963 3 Sheets-Sheet 1 IN EN TOR. Jam WHUFPMHN.

My 0; W

ATTORNEY March 196 J. w. HUFFMAN 3,24,@@

THERMOSTATIC DUAL SWITCH WITH IMPROVED MANUAL CONTROL 3 Sheets-Sheet 2 Filed May 8, 1963 fTE-l l- 200 2 2 INVENTOR.

75 254 a 222 220 j JUHN YZHUPFMHN.

ATTORNEY March 15, 1966 J. w. HUFFMAN 3,240,905

THERMOSTATIC DUAL SWITCH WITH IMPROVED MANUAL CONTROL Filed May 8, 1963 3 Sheets-Sheet 3 INVENTOR.

JUHN W.HUFFMHN.

WGiEwwW United States Patent 3,240,906 THERMOSTATIC DUAL SWITCH WITH IMPROVED MANUAL CONTROL John W. Huffman, Mansfield, Ohio, assignor to Pace, Inc., Mansfield, Ohio, a corporation of Ohio Filed May 8, 1963, Ser. No. 278,959 6 Claims. (Cl. 200-122) This invention relates to switch mechanism and more especially to a dual switch mechanism in which one circuit establishing means is manually adjustable and wherein another circuit establishing means is thermostatically controlled in conjunction with the manual control.

In certain types or kinds of instrumentalities or appliances, it is desirable if not imperative to effect the electrical energization of one current consuming instrumentality or component prior to the energization of a second electrically energizable instrumentality particularly where the latter may be dependent for its successful operation upon the prior operation of the first instrumentality. A typical example of the utility of sequentially energizable dual switch means is a conventional hair dryer unit which embodies a motor driven blower or fan which is brought into operation prior to the energization of a heating element of the hair dryer unit and wherein the heating element is de-energized prior to the de-energization of the blower or fan motor.

In conventional heater switch and blower control arrangements in use at the present time in hair dryer constructions, a blower motor circuit is first energized and thereafter resistance heaters are successively or sequentially brought into operation by step switch means but without thermostatic control, reliance for different degrees of heat being provided by a plurality of individual resistance heaters brought into sequential operation through manual adjustment. In conventional hair dryer constructions, there is no provision for attaining a gradual increase or gradual decrease in heat desired as individual resistance heaters of fixed values are employed to secure different temperatures but without gradation between fixed temperatures.

The present invention embraces a method and apparatus for initiating sequential operation of dual circuit control means whereby sequential operation of dual instrumentalities is assured.

An object of the invention is the provision of switch mechanism wherein two switch means are arranged to be sequentially adjusted by manual means and wherein one of the switch means is subservient to or controlled by a thermoresponsive media whenever the said switch means is brought into operation by the manually controlled means.

Another object of the invention is the provision of dual switch mechanism having particular utility in controlling dual current consuming instrumentalities providing reliable sequential operation in uses wherever one instrumentality is energized before a second instrumentality is energized and the second instrumentality de-energized before the de-energization of the first instrumentality.

Another object of the invention resides in a switch mechanism having dual switch means wherein both switch means are arranged to be manually adjusted and one of said switch means thereafter thermostatically controlled and the dual switch means connected in series whereby the switch means functions as a positive off for a circuit.

Another object of the invention is the provision of a switch mechanism embodying a thermoresponsive contact carrying arm in combination with an auxiliary heater intercalated in the circuit for influencing the thermoresponsive means and arranged to be shielded in a manner 3,240,906 Patented Mar. 15, 1966 to reflect radiant heat away from the region of the thermoresponsive element whereby the thermoresponsive element is primarily influenced by conducted heat from the auxlliary heater to promote longer cycling times or periods between current on and off positions.

Another object of the invention is the provision of a thermoresponsive switch means constructed and arranged to provide for ambient temperature compensation whereby the contact carried by a thermoresponsive or bimetal element and the contact carried by a manually adjustable switch arm will be in the same relative position where both are subjected to variations in room or ambient temperature conditions.

Another object of the invention is the provision of a thermostatically controlled switch mechanism having a thermoresponsive or bimetal component constructed and arranged to foster or promote a more rapid opening and closing of the switch contacts influenced by the thermoresponsive component to substantially reduce or eliminate fluttering action of the contacts during circuit making and breaking operations whereby to reduce the arcing between the contacts and correspondingly reduce the heat generated by arcing between the contacts and thereby assure more positive cycling of desired on and off periods of current flow through the switch mechanism.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economies of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is an isometric view of a switch housing enclosing the switch mechanism of the invention and illustrating schematically two current consuming instrumentalities intercalated in circuit with the switch mechanism;

FIGURE 2 is a top plan view of the manually adjustable control and indicating means for the switch mechanism;

FIGURE 3 is a plan view of the switch mechanism, the cover being shown in section;

FIGURE 4 is a sectional view taken substantially on the line 44 of FIGURE 3;

FIGURE 5 is a sectional view taken substantially on the line 5-5 of FIGURE 3;

FIGURE 6 is an isometric view of the switch housing;

FIGURE 7 is an expanded view of components of the switch mechanism in isometric illustration;

FIGURE 8 is a detail sectional view taken substantially on the line 88 of FIGURE 3;

FIGURE 9 is a top plan view of a modified form of switch mechanism of the invention, the cover being removed;

FIGURE 10 is a sectional view taken substantially on the line 1010 of FIGURE 9;

FIGURE 11 is a sectional view taken substantially on the line l111 of FIGURE 9;

FIGURE 12 is an expanded view showing in isometric illustration several components of the switch mechanism illustrated in FIGURES 9 through 11;

FIGURE 13 is a plan view illustrating a modified form of switch mechanism of the invention;

FIGURE 14 is a sectional view taken substantially on the line 14-44 of FIGURE 13;

FIGURE 15 is a fragmentary detail sectional view illustrating another modification of the switch mechanism, and

FIGURE 16 is a plan view of a switch member forming a component of the arrangement shown in FIGURE 15.

The switch mechanism of the invention is particularly adapted for controlling hair drying apparatus in which a motor operated fan or air blower and an electrically energizable heater are employed, but the switch mechanism may be advantageously employed for sequential operation of other current consuming instrumentalities. The switch means of the invention may also be utilized to secure a positive off condition of a thermostatically controlled circuit to provide for positive current interruption irrespective of the relative position of the thermoresponsive component or its ambient temperature environment.

Referring to the drawings in detail and initially to the form of the invention illustrated in FIGURES 1 through 8, the switch mechanism is mounted in a suitable housing or casing fashioned of rigid insulating material, as for example, lava or other suitable high temperature resistant insulating material. In the embodiment illustrated the switch housing 10 is preferably of substantially square configuration having a bottom portion of floor 12 and upwardly extending walls 14, one pair of opposing walls being formed with recesses or slots 16 shown in FIG- URES 6 and 8.

A cover or closure 20 of rectangular shape is provided for the housing 10 and is preferably fashioned of metal and is provided with tabs or ear portions 22 which are adapted to be received in the recesses or slots 16, the lower end regions 24 of the tabs extending inwardly over ridges 23 to secure the cover 26 to the housing 10 in the manner particularly shown in FIGURE 8. The tabs or ears 22 are fashioned with convex portions providing stressed regions to resiliently hold the end regions 24 in proper engagement with the ridges 23, as shown in FIGURE 8. The convex portions 25 serve to compensate for expansion of the cover under temperature variations set up by a heating means in the housing construction.

The base or floor 12 of the switch housing 10 is provided with notches or notched regions to accommodate three terminals 28, and 32 to which circuit leads are connected for the current supply and instrumentalit'ies controlled by the switch means. As shown in FIGURE 1, the supply line L1 is connected with the terminal 28. Terminal 30 is connected with a heating element 34 of the hair dryer unit (not shown) and terminal 32 is connected with a motor 36 operating a fan or blower for circulating air through the dryer. The other terminals of the heater 34 and the motor 36 are connected by leads 38 and 39 with the current supply line L2.

The arrangement of the invention is provided with a manually operable means for adjusting the relative position of switch means of the switch mechanism to be hereinafter described. The planar upper wall 40 of the switch cover 20 is provided with a central opening which receives the tenon portion of a bushing 42, a portion of the tenon extending within the cover 20 being swaged as shown at 44 to secure the bushing 42 to the cover. The bushing 42 is threaded internally to receive a hollow threaded shaft or stem 46 to the upper end of which is secured a manipulating knob 48 which may be molded insulating material, the knob being secured to the stem 46 by a securing screw 50.

The hollow interior of the stem 46 is threaded to accommodate an adjusting screw 52, the lower extremity of which is fashioned with a recess accommodating an end of a strut 54 of lava or other suitable rigid insulating material having high temperature resistant properties. The cover 20 is formed with a struck up or upwardly extending projection 56 which is formed by shearing a portion of the material of the upper wall 20 of the cover. Projecting laterally from the stem 46 is a stop pin 58 which is adapted to engage the projection or abutment 56 to limit rotational movement of the stem 46.

The rotational movement of the stem through its threaded engagement with the bushing 42 adjusts the position of a switch member to be hereinafter described.

The upper surface of the cover 20 is provided with a dial 60, particularly shown in FIGURE 2, and the stem 46 provided with an index or indicator 62 for cooperation with the dial 60. Where the switch mechanism of the invention is utilized for controlling a hair dryer, it is essential that the fan or blower motor 36 be energized before the heating element 34 is energized.

FIGURE 2 illustrates the knob 48 in an ofi? position, and clockwise movement of the knob 48 and the stem 46 as viewed in FIGURE 2 first actuates one switch means to energize the motor 36 driving the fan and further clockwise movement of knob 48 energizes the heating element 34. On the indicator 6% low and high positions are indicated for heating the hair dryer but the temperature of the hair dryer is thermostatically controlled in a manner hereinafter described and the setting of the knob 48 and stem 46 determines the temperature of the hair dryer through the length of duration of the periods in which current flows through the hair dryer heating element 34.

The switch mechanism of the invention is inclusive of dual switch means, one switch means 64 being arranged to control the circuit of the blower or fan motor 36 and the second switch means 66 arranged to control the energization and de-energization of the heating element 34 through manually adjustable and thermostatically controlled means. The switch means 64 includes a switch arm or member 7d of L-shape, as shown in FIGURE 7, having a shank or body portion 72 and the projecting leg portions '73.

The switch member 70 together with other components of the switch mechanism are supported on a pin or rivet '75 having a head portion 76, as shown in FIGURE 5. The terminal 28 is secured in position by a rivet 75 which, after assembly of the switch components is swaged to form a head 77. As shown in FIGURE 7, the switch :arm 76 is provided with an opening '73 through which extends the rivet 75. The switch member '70 is provided with a second opening 8% through which extends the insulating strut 54. The projecting portion or leg '73 of switch member 70 is provided with a contact 82, shown in FIGURE 4.

As shown in FIGURE 4, the housing or casing 10 is fashioned with a boss portion or ledge 84 having an opening accommodating a tubular rivet or pin 85, the interior of the rivet or pin being threaded to accommodate a threaded tenon 85' secured to or forming an extension of a contact 86 of silver or other suitable material adapted for cooperation with the contact 32 carried by the relatively movable or flexible switch arm '70. The end of the threaded tenon 85 is formed with a kerf to accommodate a tool inserted through the hollow interior of the rivet 85 in order to adjust the relative position of the contact $6. The rivet 85 extends through an opening in terminal 32 and serves to retain the terminal in fixed position, the end of the hollow rivet 85, after assembly, being swaged to form a head 87 adjacent and engaging the terminal 32. The cooperating contacts 82 and 86 control the circuit through the blower motor 36 illustrated schematically in FIGURE 1.

The second switch means 66 includes a switch arm 90 of L-shaped configuration including a body or shank portion 92 and a laterally extending leg portion or projection 93, shown in FIGURE 7, provided with a contact 95. The body or shank portion 92 of switch member 90 has on opening 94 to receive the rivet 75, as shown in FIGURE 5. In assembly, the body portion of switch member 70 is contiguous with the shank or body portion 92 of the second switch member 96, the leg portion 73 of switch member 70 extending in a right-hand direction as viewed in FIGURE 3, and the leg portion 93 of switch member 90 extending in a left-hand direction as viewed in FIGURES 3 and 4.

The switch mechanism is inclusive of a thermoresponsive component or element 98 which is fashioned of two metals having dissimilar coefficients of expansion whereby the element is deflected under variations in ambient temperature conditions. The thermoresponsive element 98 is provided with an opening 100, shown in FIGURE 7. Assembled on the pin or rivet 75, shown in FIGURE 5, is an insulating bushing or member 102 provided with a tenon portion 104. The thermoresponsive element 98 is mounted on the insulating bushing 102, the opening 100 accommodating the tenon portion 104. The bushing 102 may be made of high temperature resistant ceramic material or lava.

Secured to an end region of the bimetallic element 98 is a member or element 106 which is secured to the bimetallic element by means of a rivet 108, or other suitable securing means.

The member or element 106 at its terminal region is provided with a contact 110' adapted for cooperation with the contact 95 carried by the switch member 90. The cooperating contacts 95 and 110 control the circuit through the heating element 34, shown schematically in FIGURE 1.

The member or element 106 may be fashioned of bimetallic material or strip but inverted with relation to the bimetallic element 98 whereby ambient temperature variations will cause the member 106 to flex in a direction opposite to that of the bimetallic element 98 for a purpose hereinafter explained. The element 106 is preferably of lesser length than the bimetallic element 98 so that ambient temperature variations affect the bimetallic element 98 to move the contact 110 though the element 106 of inverted bimetallic material partially ofisets or counteracts a portion of the movement of the bimetallic element 98.

The extension or element 106 may be fashioned or nonthermoresponsive material such as stainless steel or the like which, as hereinafter explained, provides a similar action in association with the bimetallic element 98. With particular reference to FIGURE 5, the bimetallic element 98 is disposed so that upon an increase in ambient temperature conditions, the bimetallic element 98 is flexed downwardly to move the contact 110 carried thereby in a direction away from the contact 95.

A supplemental heating element 116 is embodied in the switch mechanism for establishing beat to influence the bimetallic element 98 when the contacts 95 and 110' are in circuit-closing position establishing a circuit through the heating element 34, shown in FIGURE 1. With particular reference to FIGURE 4, a rivet 114 secures the terminal member 30 to the housing 10. One end of the supplemental resistance heater or heating element 116 surrounds the rivet 114 within the housing adjacent the head 118 of the rivet.

The opposite end region 120 of the supplemental heating element 116 is disposed beneath and in contact with a metal plate 122, shown in FIGURES 5 and 7, the plate 122 having an opening 124 through which extends the tenon 104 of the bushing 102 to insulate the plate 122 from the rivet 75. As shown in FIGURE 5 a metal collar or spacer 126 surrounds the tenon 104 to properly space the bimetallic element 98 and the plate 122 and convey current to the bimetallic element 98.

The purpose of the supplemental heater 116 is to establish heat adjacent the bimetal element 98 during the periods that the current flows through the main heating element 34 shown in FIGURE 1. While it is essential to thermoresponsive control of the circuit through the contacts 95 and 110 to provide the supplemental heater 116 for increasing the temperature of the environment ambient the bimetal element 98, it is preferable that the major amount of heat generated by the heater 116 be conducted by the metal of the heater and the plate 122 to the bimetal element 98.

The heater 116 generates radiant heat and excessive radiant heat causes too rapid cycling or operation of the bimetal element 98. Hence in most uses for the switch mechanism it is desirable to reduce or retard the effect of radiant heat on the bimetallic element 98. In order to retard or reflect the radiant heat, a thin layer of mica 130 is disposed above the heater 116 so as to cover the heater. Disposed above the layer 130 of mica is a layer of metal foil 132 coextensive with the mica layer 130 and, above the layer of foil 132, is a second layer of mica 134.

The foil 132 is therefore contained between the mica layers 130' and 134 so that the foil is insulated by the layers of mica. The metal foil serves the purpose of reflecting or retarding flow of radiant heat from the heater 116 toward the bimetallic element whereby the current on periods may be of greater duration than is possible where the radiant heat from the heater 116 is unimpeded.

It is to be understood that the current supplied to the primary heater 34 of a hair dryer unit or other instrumentality connected in circuit with the contacts 95 and 110 receives its current flow through the supplemental heater 116. Where the heater 34 does not consume a large amount of current so that heat generated by current flow through the supplemental heater 116 is not excessive, the reflective insulation provided by the layer of foil 132 may be dispensed with.

The operation of the switch mechanism shown in FIG- URES 1 through 7 as utilized for controlling a hair dryer unit wherein the heating element 34 is the heating element in the hair dryer unit and the motor 36 operates an air circulating means or blower, is as follows: The switch members and are normally prestressed upwardly in a direction separating the contacts 82 and from their cooperating contacts 86 and 110. Thus when the control member 48 is in the off position the circuits through both switch arms 70 and 90 are open.

In the use of a conventional hair dryer, it is essential that the air circulating means provided by a blower be energized and in operation prior to the energization of the circuit through the hair dryer heating element 34. In initiating the use of the dryer the operator rotates the knob 48 in a clockwise direction as viewed in FIGURES 1 and 2 from an 011 position to the position indicating the degree of heat desired to be maintained in the hair dryer unit.

The initial rotary movement of knob 48 from an off position, through the strut 54, flexes the switch member 90 downwardly as viewed in FIGURES 4 and 5 and the stressed condition of the switch member or arm 70 causes the arm 70 to move downwardly following the downward flexure of the switch member or arm 90. This initial movement engages the contacts 82 and 86 to energize the motor 36 operating the air circulator or blower.

A position on the dial 60 designated fan indicates the setting of the knob 48 to initiate the operation of the blower without the energization of the circuit through the heating element 34.

Further rotational movement of the knob 48 in a clockwise direction flexes the switch arm 90 further downwardly and engages the contact 95 carried thereby with the contact carried by the bimetallic or thermoresponsive means 98 and 106 to thereby energize or complete a circuit through the hair dryer heating element 34. The relative rotational position of the control knob 48 between the designations low and high is determinative of the position of the switch arm 90 at which the heated environment provided by the heater 116 affects the bimetallic element to effect disengagement of the contact 110' from the contact 95 through flexure of the bimetal element 98.

Through this means the temperature of the hair dryer unit may be maintained at a desired temperature by regulation of the knob 48 between the low and high positions provided on the dial 60. The amount of heat for the hair dryer unit generated by energization of the heating element 34 is determined by the duration of the on periods of the heating element controlled through the heat responsive movements of the bimetal element 98. During on periods the same amount of current flows through the heating element 34 but the hair dryer temperature is varied by the duration of the current on positions controlled by the fiexure of the bimetal element 98.

The action of a bimetallic strip may be comparatively slow in its action particularly where the temperature change in the region of the thermostat is comparatively slow. This condition results in a so-aclled creeping" action of the thermostat or bimetal means preventing an abrupt or defined making or breaking of the circuit through the contacts 95 and 110. Thus when the stress in the thermoresponsive element under ambient heat conditions approaches the critical position of engaging and disengaging the contact 110 with the contact 95, a minute movement of the movable contact causes substantial arcing of current between the contacts establishing substantial heat.

The heat from the arc is substantial and aifects the thermoresponsive element in a direction to separate the contacts 110 and 95. This additional heat from the are transmitted to the bimetallic element is seen dissipated and the contact 11 again approaches a position to engage the contact 95 and a repetition of the arcing or fluttering ensues.

The foregoing described action of a thermoresponsive element tends to occur where the entire support for the movable contact is a continuous strip of bimetal. The provision of the short length of material 1% attached to the bimetal element 98 functions to reduce the fluttering action of the contacts during 3. making or breaking of the circuit through engagement or disengagement of the contacts 95 and 110.

The extension element 106 secured to the bimetal element 98 may be fashioned of a bimetal strip but inverted so that the heat generated by arcing between contacts 95 and 110 is effective to flex the short bimetallic strip 106 in a direction to either positively make or break the circuit depending upon the direction of movement of the bimetal element 98.

It is found that the extension or element 106 may be fashioned of stainless steel in lieu of a bimetallic element and obtain substantially the same action. Stainless steel is a relatively poor conductor of heat and it is believed that the element 106 fashioned of stainless steel, retards the transfer of heat caused by arcing at the contacts from reaching and adversely aifecting the bimetal element 98 and thereby secure a more positive and faster engagement or disengagement of the contacts 95 and 110 with a minimum of arcing.

This arrangement greatly improves the sensitivity of the control of the hair dryer heating element 34 as the bimetal element 98 with the extension 106 provides a more positive making or breaking of the contacts and hence a more reliable control of the energization and deenergization of the heating element 34.

Another feature of the switch of the invention is that when the operator desires to de-energize the hair dryer unit, rotation of the control knob 48 in a counterclockwise direction first disengages the contact 95 from the contact 114 to deenergize the heater 34 and upon further movement of the knob to off position, effects a sub sequent disengagement of the contact 82 from the contact 86 to de-energize the blower motor 36.

Through this arrangement a safety factor is provided in that the air circulating means operated by the motor 36 is brought into operation before the primary heating element 34 is energized and continues to function until after the switch member 90 disengages the contact 95 from contact 110 so that whenever the heating element 34- is energized, the air circulating means operated by the motor 36 is in operation.

FIGURES 9 through 12 illustrate a modified switch means of the invention. In this form of the invention the switch housing 16' is identical with the switch housing 10 and the cover or closure 20' is the same as the switch housing cover 20, the latter being held in assembled relation with the housing 10' by the means shown in FIG- URE 8. The arrangement shown in FIGURES 9 through 12 includes terminal members 28', 30' and 32 for incorporation in the hair dryer unit circuits as illustrated schematically in FIGURE 1.

The arrangement includes a manually adjustable means for controlling components of the switch mechanism. The manually adjustable means includes a bushing having a tenon portion extending through an opening formed in the cover or closure 20' and sw-aged as shown at 152 to secure the bushing 158 to the closure 20. The exterior surface of the bushing 150 may be threaded as shown at 154 to accommodate threaded nuts (not shown) for securing the bushing 150 to a housing or support forming a component of the hair dryer unit construction.

The interior of the bushing 151 is threaded to accommodate a threaded shaft 156, the upper end being provided with a manipulating knob 15? for rotating the shaft 156 with respect to the bushing 150, the upper end of the shaft being secured to the knob 158 by means of a setscrew (not shown). The bushing 150 is provided with an abutment member 160 and the manipulating knob 158 provided with a pin or stop member 162 which is adapted for engagement with the abutment 166 to limit the rotational movement of the knob 158 and the shaft 156.

The interior of the shaft 156 is bored and threaded to accommodate a threaded member or screw 164 which is provided at its lower end with a conical recess 166 receiving the upper end of a lava strut 168- which is engageable with a switch member as hereinafter explained. The arrangement shown in FIGURES 9 through 12 includes a first switch means 178 and a second switch means 172. The first switch means is adapted to control the circuit of the fan or blower motor 36 and the second switch means 172 employed for controlling the heating element 34-, shown schematically in FIGURE 1.

The first switch means 178 includes a manually adjustable switch arm 174 which has an opening at one end region to be received upon a rivet or pin 176, the latter having a head 177. After assembly of several components on the rivet as hereinafter described, the other end region of the rivet is swaged as shown at 178 in contact with the terminal 28 to secure the terminal and switch components in assembled relation. The switch member or switch arm 174'. has a laterally projecting portion 180 provided with a contact 182.

A bracket 184 has an offset ear portion 186 provided with an opening to receive a rivet 188 which is swaged, as shown at 189, into engagement with the terminal member 32' and serves to secure the terminal 32' and the bracket 18% in the position illustrated in FIGURES 9 and 10. The bracket 184 is provided with a threaded opening to receive a threaded member 190 provided with a contact 192 for cooperation with a contact 182 to control a circuit through the fan or blower motor 36 shown in FIGURE 1.

The second switch means 172 is inclusive of a switch arm or switch member 196 having a transversely extending projecting portion 198 carrying a contact 200, as particularly shown in FIGURES 9 and 10. The lower end of the lava strut 168 engages the upper surface of the switch arm 1%, the body portions of the switch arms 17 i and 196 being contiguous as shown in FIGURE 11. The end region of the switch member 196 opposite the projection 198 is fashioned with an opening to facilitate its assembly on the rivet 176 in the manner shown in FIGURE 11.

Also assembled on the rivet 176 is an insulating bushing 2.614 of lava, ceramic or other high temperature re sistant insulating material, the bushing 204 having a tenon portion 206. The upper end of the bushing 204 is in engagement with the lower surface of the switch member 174. The switch means 172 includes a second switch member 208 having an opening adjacent one end to facilitate its assembly on the tenon portion 206 of the insulating bushing 204, as shown in FIGURE 11.

The switch member 208 is preferably fashioned with downwardly turned flanges 210 at its lengthwise edge regions, the flanged region of the switch arm terminating at a neck portion 212 which is of reduced cross-section so that flexure will occur at the region of the neck portion 212. The distal end of the switch member 208 is provided with a contact 214 which cooperates with a contact 200 for controlling the circuit of the heater 34 shown in FIGURE 1 through the terminal connections 28 and 30'. It will be noted from FIGURE 9 that the switch member 208 is angularly arranged with respect to the bodies of the switch members 174 and 196 to facilitate cooperation of contact 214 with contact 200.

The switch member 208 is adapted to be controlled by a thermoresponsive means or bimetallic means. The thermoresponsive means illustrated includes a bimetallic element 220 fashioned of metals having dissimilar coefiicients of expansion to obtain a thermoresponsive action or flexure under the influence of ambient temperature variations. Secured to the distal end of the bimetallic element 220 is an insulating strut 222 of ceramic, lava or other suitable high temperature resistant material secured to the bimetallic element by a clip 223.

The upper end of the strut 222 is adapted to engage the lower surface of the switch arm 208 to influence the position of this switch arm under temperature variations causing flexure of the bimetallic element 220.

The bimetallic element is fashioned at the end region opposite the strut 222 with an opening to facilitate its assembly on the tenon portion of bushing 204 in the manner shown in FIGURE 11. A metal collar 223 surrounding the tenon portion of bushing 204 spaces the bimetallic element 220 from the switch arm 208.

A supplemental heating means is provided for influencing the bimetallic element 220 when current flow is established through the primary heater 34 of the hair dryer or other instrumentality. In the embodiment shown in FIGURES 9 through 12, the supplemental or auxiliary resistance heater or heating element 230 is of zig-zag shape having one end curled about a rivet 232 and beneath the rivet head 234, the opposite end of the rivet 232 being swaged at 236 in contact with the terminal member 30'. The heater strip 230 is arranged contiguous with and supported by the floor 12' of the housing The opposite end region 238 of the heater strip 230 engages a current conducting plate 240, the latter having an opening 242 to be received upon the tenon portion 206 of the bushing 204 as shown in FIGURE 11, a metal collar 242 surrounding the bushing 204 and spacing the bimetallic element 220 from the plate 240 as shown in FIGURE 11. The end 238 of the heating element 230 contacts the plate 240 to establish the circuit through the heating element 230.

It will be seen from the foregoing that a circuit through the second switch means is established from the terminal 30' through the rivet 232, supplemental heater 230, plate 240 through the metal collars 242 and 224 and the bimetallic element 220 to the switch arm 208. When the contacts 200 and 214 are in engagement a circuit is completed through the switch arm 196 and the rivet 176 to the terminal 28.

In the arrangement shown in FIGURES 9 through 12, the switch arms 174 and 196 are initially prestressed downwardly so that in the off position of the knob 158, both sets of switch contacts 192, 182 and 200, 214 are out of engagement as shown in FIGURE 10 to interrupt current flow through both the blower motor circuit and the heater circuit. The direction of the thread on the shaft 156 is such that the rotation of the manipulating knob 158 away from off position permits the strut 168 to move slightly upwardly under the influence of the initial stress of the switch arms, engaging the contact 182 with the contact 192 to energize the circuit through the blower motor 36, shown in FIGURE 1.

The switch arm 196 follows the upward movement of the strut 168 and, depending upon the particular setting of the knob 158, the contacts 200 and 214 are engaged to complete a circuit through the heating element 34 shown in FIGURE 1.

Thereafter the bimetallic element 220 being influenced by the heat generated by current flow through the resistance heater 230 is distorted or flexed to influence the position of the switch arm 208 and thereby regulate the cycles or periods of current flow through the heater 34 through the making and breaking of the contacts 200 and 214 responsive to deflections of the bimetallic element 220. In this manner the heating element 34 is intermittently energized to thereby control the heating of the hair dryer unit.

If desired the layers of insulating material such as mica and the reflective foil 132 shown in FIGURE 4 may be embodied in the arrangement shown in FIGURES 9 through 12 in order to reduce or reflect the radiant heat from the resistance heater 230 and thereby reduce the number of current on and OK cycles in the control of the temperature of the hair dryer.

FIGURES 13 and 14 illustrate a modified form of switch means of the invention. This form of the invention is similar to that shown in FIGURES 3 and 4 and includes a housing 10a having a cover or closure 20a. The housing 10a is provided with terminals 28a, 30a and 32a for connection in circuits of the character illustrated in FIGURE 1. The terminal 32a is secured in position by means of a rivet a which is provided at its upper end with a contact 86a. If desired, the rivet 85a may be threaded interiorly to accommodate a threaded extension on contact 86a for adjusting the contact as shown in FIGURE 4.

The switch arm 70a has a projecting leg portion 7311 provided with a contact 82a for cooperation with a contact 86a to control the circuit through the fan or blower motor 36, shown in FIGURE 1. The switch arm 70a is supported in the same manner as shown in FIGURES 3 through 5. A strut 54a is associated with a manipulating shaft 46a threaded into a stationary bushing or collar 420, the shaft 46:: being provided with a manipulating knob 48a, this construction being the same as that shown in FIGURES 3 through 5.

The switch means, in this form of the invention, for controlling the heating element 34, shown in FIGURE 1, includes a switch arm 250 supported by the rivet 75a in the same manner that the switch member 90 is supported in FIGURE 5. The distal end of the switch arm 250 is provided with a contact 252 which cooperates with a contact 254 supported at the distal end of a bimetallic element 256, which is mounted by an insulating bushing surrounding the rivet 75a in the same manner as shown in FIGURE 5.

The rivet 114a secures the terminal 30a to the housing 10a. Disposed between the floor of the housing and the head of the rivet 114a is one terminal or end of the supplemental heating element 116a. The opposite end 120a of the heating element 116a engages a metal plate 260 in contact with a metal spacing collar 104a in contact with the bimetallic element 256 carrying the contact 254. As shown in FIGURE 14, the strut 54a extends through an opening in the switch member 70a, the terminal end of the strut engaging the upper surface of the switch member 250.

In this form of construction the switch member 250 is prestressed in a upward direction whereby the sets of contacts are normally disengaged when the strut 54a and the knob 48a are in an off position. The construction shown in FIGURES 13 and 14 functions in the same manner as the switch mechanism illustrated in FIGURES 3 through 5 When the manipulating knob 48:: is rotated slightly from an off position, such rotational movement moves the strut 54a downwardly permitting the contact 82a on the switch arm 70a to engage the contact 86a and complete the circuit through the blower motor 36.

Further rotation of the manipulating knob 48a moves the switch arm 250 to a position at which it is desired to maintain a predetermined temperature for the hair dryer heating unit, and thereafter the thermoresponsive or bimetallic element 256 through cooperation of the contacts 252 and 254 makes and breaks the circuit through the heating element 34 and the supplemental heating element 116a.

A further modification of the invention is illustrated in FIGURES 15 and 16. This form is similar to the construction shown in FIGURES 13 and 14 except that the switch arm 70:! and the switch arm 250, shown in FIGURE 14, are combined into one switch member 270. The housing b is the same as the housing 10a and the closure member (not shown) supports a manipulating means for the switch arm 270 of the same character as that illustrated in FIGURE 14, the manipulating means controlling the position of a strut 272, shown in FIG- URE 15, which is in engagement with the upper surface of the switch member 270.

The bimetallic element 252]) and the supplemental heating element 116k and the mounting therefor is the same as that shown in FIGURE 14, the heater Heb being connected to the rivet 11411 in electrical contact with the terminal 30b. The switch arm 270 is in electrical contact with the terminal 28b. The terminal 32b is secured to the housing ltlb by a rivet 85b which is provided with a contact 86b. The switch arm 270 is fashioned with an integral laterally-projecting portion 2276 con nected with the body portion of the switch member by a weakened zone indicated at 278, the weakened zone or zone of fiexure being provided by a notch 280 at the region joining the projection 276 with the body portion of the switch member 270.

The projecting portion 276 of the switch member 270 is equipped with a contact 82b which cooperates with the contact $6b to control the circuit through the fan or blower motor 36, shown in FIGURE 1. The body portion of the switch member 270 is provided with a contact 282 which cooperates with a contact 284 carried by the bimetallic element 252b, the contacts 282 and 284 cooperating to control the circuit through the hair dryer heating element 34, shown in FIGURE 1.

The operation of the construction shown in FIGURES 15 and 16 is simlar to the operation of the arrangement shown in FIGURES 13 and 14 except that the strut memher 272 engages the switch member 27%.

When the operator rotates the manipulating knob from an off position, the movement through the threaded connection of the knob with the means engaging the strut 272 moves the strut slightly downwardly which movement brings the contact 8211 into engagement with the contact 86b to energize the circuit through the blower motor 236.

Further downward movement of switch member 27% by further rotational movement of the manipulating knob will cause slight fiexure or distortion of the switch member 270 provided for by the weakened zone 273 which permits the portion carrying the contact 282 to move downwardly an increased distance even though the contact 8212 has been engaged with the contact 851) to prevent further downward movement of that portion of the projection 276 adjacent the contact 82b.

Thus through the provision of the weakened zone 278, the contact 82b and contact 282 may be supported upon a single member fashioned or configurated by the weakened zone 278 provided through the cutaway portion 280 to permit ficxure of that portion of the switch arm carrying the contact 282. The bimetallic element 252b, under the influence of heat from the supplemental heater 116b, controls engagement and disengagement of the contacts 232 and 2334 to control the circuit through the hair dryer heating element 34.

While the forms of the invention have been illustrated as particularly adaptable for controlling the circuits for an air circulating means and a heating instrumentality, it is to be understood that the switch means may be utilized for controlling other instrumentalities particularly where it is desirable that they be energized or de-energized in sequence.

The switch mechanism of the invention may be employed as a positive off switch means to assure a positive interruption in current flow when the manipulating knob is in off position. To adapt the switch mechanism for this purpose, the sets of contacts are connected in series with the instrumentality to be controlled.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

ll. Switch mechanism comprising, in combination, a housing, a first switch means in the housing including a first pair of cooperating contacts of a first circuit, a second switch means in said housing including a second, pair of cooperating contacts of a second circuit, manually rotatable means threadedly mounted by the housing and adjustable to control the relative position of a contact of each pair, thermoresponsive means in said housing movable to control the relative position of a contact of the second pair of contacts, electrically energizable heating means in said housing in circuit with the second pair of contacts and disposed adjacent the thermoresponsive means whereby heat generated by the heating means influences the thermoresponsive means, the contacts controlled by the manually rotatable means being actuated by rotation of the rotatable means from an off position to engage the contacts of the first pair prior to engaging the contacts of the second pair.

2. Switch mechanism comprising, in combination, housing means, a pin carried by the housing means, a bushing of insulating material surrounding a portion of the pin, switch means including a member mounted upon and in contact with the pin, a first contact, a first contact means controlled by said member and cooperable with said first contact for controlling a first circuit, a second contact supported within the housing means for relative movement, thermoresponsive means supported by said insulating bushing arranged to influence the position of said second contact, a second contact means in said housing means controlled by said member and cooperable with the second contact for controlling a second circuit, an electrically energizable resistance heater in said housing means adjacent the thermoresponsive means whereby heat from the heater influences the thermoresponsive means, and a layer of insulating material disposed on the resistance heater.

3. Switch mechanism comprising, in combination, housing means, a pin carried by the housing means, a bushing of insulating material surrounding a portion of the pin, switch means including a member mounted upon and in contact with the pin, a fixed contact supported by the housing means, a first contact means in said housing means controlled by said member and cooperable with said fixed contact for controlling a first circuit, a second contact in said housing means supported for relative movement, thermoresponsive means supported by said insulating bushing to influence the position of said second contact, a relatively movable second contact means in said housing means controlled by said member and cooperable with the second contact for controlling a second circuit,

and an electrically energizable heating means in said housing means and intercalated in said second circuit whereby heat from the heating means influences the relative position of the thermoresponsive means.

4. Switch mechanism for concomitantly controlling an electrically energizable heating unit and a motor-operated air circulating means, including, in combination, a housing, a first switch means supported in said housing including a first pair of cooperating contacts in circuit with the motor of the air circulating means, a second switch means supported in said housing including a second pair of cooperating contacts in circuit with the heater of the heating unit, manually operable means mounted in the housing and being adjustable for controlling one contact of each pair of contacts, thermoresponsive means supported in the housing for controlling the relative position of the other contact of the second pair, and a supplemental electrically energizable heater in said housing whereby the heat therefrom influences the relative position of the thermoresponsive means to control the circuit through the second pair of contacts.

5. Switch mechanism comprising, in combination, a support, a first switch means mounted on the support including a first pair of cooperating contacts of a first circuit, a second switch means mounted on the support including a second pair of cooperating contacts of a second circuit, manually operable means carried by the support and being adjustable for controlling the relative position of a contact of each pair, thermoresponsive means mounted on the support for influencing the position of a contact of the second pair of contacts, electrically energizable heating means in circuit with the second pair of contacts and disposed adjacent the thermoresponsive means whereby heat generated by the heating means influences the thermoresponsive means, said manually operable means controlling a contact of each of said first and second pairs of contacts whereby a circuit is established through the first pair of contacts during the periods that a circuit is established through the second pair of contacts, said thermoresponsive means including a bimetallic strip, an extension member secured to the bimetallic strip and carrying the contact movable with the thermoresponsive means, said extension being of a mate rial adapted to reduce the influence of heat generated by arcing during making and breaking of the contacts of the second pair on the bimetallic strip.

6. Switch mechanism comprising, in combination, support means, a switch member mounted on the support means, manually operable means mounted on the support means to adjust the relative position of the switch member, a first contact mounted on the support means, means mounting a second contact for movement relative to the switch member, thermoresponsive means mounted by the support means arranged to influence the position of the second contact, contact means controlled by manual movement of the switch member for engagement and disengagement with said first and second contacts, the contact means being disposed with respect to the switch member whereby movement of the switch member by the manually operable means engages and disengages the contact means with the first and second contacts in sequence.

References Cited by the Examiner UNITED STATES PATENTS 2,338,474 1/ 1944 Wilson 200-413 2,410,014 10/1946 Clark 219-20 2,566,270 8/ 1951 Weiland 200139 X 2,767,293 10/ 1956 Jordan et al.

2,805,302 9/1957 Reis 200122 2,847,553 8/1958 Smith 200-122 X 2,924,700 2/ 1960 Huffman 200-122 X 2,930,874 3/1960 Andrews 200138 BERNARD A. GILHEANY, Primary Examiner. 

1. SWITCH MECHANISM COMPRISING, IN COMBINATION, A HOUSING, A FIRST SWITCH MEANS IN THE HOUSING INCLUDING A FIRST PAIR OF COOPERATING CONTACTS OF A FIRST CIRCUIT, A SECOND SWITCH MEANS IN SAID HOUSING INCLUDING A SECOND, PAIR OF COOPERATING CONTACTS OF A SECOND CIRCUIT, MANUALLY ROTATABLE MEANS THREADEDLY MOUNTED BY THE HOUSING AND ADJUSTABLE TO CONTROL THE RELATIVE POSITION OF A CONTACT OF EACH PAIR, THEREMORESPONSIVE MEANS IN SAID HOUSING MOVABLE TO CONTROL THE RELATIVE POSITON OF A CONTACT OF THE SECOND PAIR OF CONTACTS, ELECTRICALLY ENERGIZABLE HEATING MEANS IN SAID HOUSING IN CIRCUIT WITH THE SECOND PAIR OF 